Ethics, also known as moral philosophy, is a branch of philosophy that involves systematizing, defending, and recommending concepts of right and wrong conduct. The term comes from the Greek word ethos, which means "character". Ethics is a complement to Aesthetics in the philosophy field of Axiology. In philosophy, ethics studies the moral behavior in humans, and how one should act.
Ethics may be divided into four major areas of study:

Meta-ethics, about the theoretical meaning and reference of moral propositions and how their truth values (if any) may be determined;

Normative ethics, about the practical means of determining a moral course of action;

Applied ethics, about how moral outcomes can be achieved in specific situations;

Descriptive ethics, also known as comparative ethics, is the study of people's beliefs about morality;

Postmodern ethics

The 20th century saw a remarkable expansion and evolution of critical theory, following on earlier Marxist Theory efforts to locate individuals within larger structural frameworks of ideology and action.

Antihumanists such as Louis Althusser and Michel Foucault and structuralists such as Roland Barthes challenged the possibilities of individual agency and the coherence of the notion of the 'individual' itself. As critical theory developed in the later 20th century, post-structuralism sought to problematize human relationships to knowledge and 'objective' reality. Jacques Derrida argued that access to meaning and the 'real' was always deferred, and sought to demonstrate via recourse to the linguistic realm that "there is nothing outside context" ("il n'y a pas de hors-texte" is often mistranslated as "there is nothing outside the text"); at the same time, Jean Baudrillard theorised that signs and symbols or simulacra mask reality (and eventually the absence of reality itself), particularly in the consumer world.

Post-structuralism and postmodernism argue that ethics must study the complex and relational conditions of actions. A simple alignment of ideas of right and particular acts is not possible. There will always be an ethical remainder that cannot be taken into account or often even recognized. Such theorists find narrative (or, following Nietzsche and Foucault, genealogy) to be a helpful tool for understanding ethics because narrative is always about particular lived experiences in all their complexity rather than the assignment of an idea or norm to separate and individuated actions.

Zygmunt Bauman says Postmodernity is best described as Modernity without illusion, the illusion being the belief that humanity can be repaired by some ethic principle. Postmodernity can be seen in this light as accepting the messy nature of humanity as unchangeable.

David Couzens Hoy states that Emmanuel Levinas's writings on the face of the Other and Derrida's meditations on the relevance of death to ethics are signs of the "ethical turn" in Continental philosophy that occurred in the 1980s and 1990s. Hoy describes post-critique ethics as the "obligations that present themselves as necessarily to be fulfilled but are neither forced on one or are enforceable" (2004, p. 103).

Hoy's post-critique model uses the term ethical resistance. Examples of this would be an individual's resistance to consumerism in a retreat to a simpler but perhaps harder lifestyle, or an individual's resistance to a terminal illness. Hoy describes Levinas's account as "not the attempt to use power against itself, or to mobilize sectors of the population to exert their political power; the ethical resistance is instead the resistance of the powerless"(2004, p. 8).

Hoy concludes that

The ethical resistance of the powerless others to our capacity to exert power over them is therefore what imposes unenforceable obligations on us. The obligations are unenforceable precisely because of the other's lack of power. That actions are at once obligatory and at the same time unenforceable is what put them in the category of the ethical. Obligations that were enforced would, by the virtue of the force behind them, not be freely undertaken and would not be in the realm of the ethical. (2004, p.184)

In present day terms the powerless may include the unborn, the terminally sick, the aged, the insane, and non-human animals. It is in these areas that ethical action in Hoy's sense will apply. Until legislation or the state apparatus enforces a moral order that addresses the causes of resistance these issues will remain in the ethical realm. For example, should animal experimentation become illegal in a society, it will no longer be an ethical issue on Hoy's definition. Likewise one hundred and fifty years ago, not having a black slave in America would have been an ethical choice. This later issue has been absorbed into the fabric of an enforceable social order and is therefore no longer an ethical issue in Hoy's sense.